This invention relates to dental implants and, more particularly, to detachable posts for implants.
A dental implant, such as that described in U.S. Pat. No. 3,465,441 and U.S. Pat. No. 3,660,899 of Dr. Leonard I. Linkow are used to support an artificial bridge, tooth or other dental prosthesis. The implant has an implant portion, e.g. in the form of a blade, that is secured in the underlying bone in an edentulous span. A linking or neck portion, e.g. in the form of a screw thread, extends up from the implant portion and is attached to a support or post portion on which the artificial bridge or crown is attached. This type implant is inserted by making an incision in tha fibromucosal tissue down to the underlying alveolar ridge crest bone. The tissue is then reflected to expose the bone and a burr is used to create a groove in the bone which is as deep as the implant portion. Using a mallet, the implant portion is tapped into the bone. After the insertion, the tissue is sutured about the neck portion so that the post protrudes above the tissue line. Typically, a few weeks or months are allowed to pass before the dental prosthesis is attached to the post. During this period, bone starts to grow around the implant portion and through holes provided in it, thereby acting to anchor the implant in place before it is stressed by use.
Submergible blade implants, such as that shown in U.S. Pat. No. 4,177,562 of A. L. Miller and A.J. Viscido, allow a blade to be inserted in the jawbone for a long period of time before being placed in actual use. With this type of implant, the blade is completely submerged in the bone. It is then covered over and allowed to remain in place for several months. Once there has been substantial regrowth of the bone around and through the submerged blade, the tissue is again opened and an integral neck and post assembly is attached to the blade by a typical screw connection.
Removable posts, such as the screw type shown in U.S. Pat. No. 3,660,899 or U.S. Pat. No. 4,177,562, are necessary with submergible implants which are to remain out of use for a period of time while the bone regrows. Screw posts are also useful with non-submergible implants because they allow a good blade to remain in place when a defective bridge is removed. This is accomplished by cutting the bridge into sections in order to allow the post to be turned for removal of the post from the blade. In some cases, however, it is the blade which is defective. Nevertheless, current practice requires that the perfectly good bridge, which is permanently cemented over the posts, be destroyed in order to allow the posts to be unscrewed and the defective implant blade replaced.